





«b^ 



^ 







*°* 








^°** 










» ^ 









"fev* 



%<** 



*w - 










"oV* 






^°^ 



«5*2ft 




^ ^ 

W 






'• A' 



4^°^ ° 

'Jo. * • I n • av" 



3% 




**' %••••■' <'" 




S.""^ V 







4°* 



^r> *'o. t 













/ .-isK*. ^^ .-ate-, \/ 
















-? 




^S> "o . » 







' > .iS^.>*. /.c^:-% >*.j5K>V A.^fe.% ,**.-^:-.V c 



iP*. 






. V^>* V ; - : V VW V-- T > V*^> \°>zf^ 



P * A* "%> • 






;• A* % 




^> jA • V^y'» «£ 





* a>«^ - 

-J* 






'by' 



a* •i'i- ^ v\.i£% %> *i 



f p"^ V 

•^ *. *« 



^ 









^0 



.4 Oft 



'• A^ 

* A^ ^ • 











'•^ '•••".A " ^ •••'•' v^ 






^a^ ^ %UK« ^ ^ 






?»• ^ cA * 

</> ^ • 

* A^ *+ •, 














»ffi\ 



^. ^ -«"< 






IIIIIIIIIMII 1111 



IC 



111111111111111111 



9246 



BUREAU OF MINES 
INFORMATION CIRCULAR/1990 



Assessment of Accident Risk During 
Haulage Truck and Power Shovel 
Maintenance and Recommendations 
for Improved Safety 

By Thomas J. Albin 




U.S. BUREAU OF MINES 
1910-1990 



THE MINERALS SOURCE 



*4U OF ^ 



Mission: As the Nation's principal conservation 
agency, the Department of the Interior has respon- 
sibility for most of our nationally-owned public 
lands and natural and cultural resources. This 
includes fostering wise use of our land and water 
resources, protecting our fish and wildlife, pre- 
serving the environmental and cultural values of 
our national parks and historical places, and pro- 
viding for the enjoyment of life through outdoor 
recreation. The Department assesses our energy 
and mineral resources and works to assure that 
their development is in the best interests of all 
our people. The Department also promotes the 
goals of the Take Pride in America campaign by 
encouraging stewardship and citizen responsibil- 
ityforthe public landsand promoting citizen par- 
ticipation in their care. The Department also has 
a major responsibility for American Indian reser- 
vation communities and for people who live in 
Island Territories under U.S. Administration. 



Information Circular 9246 



Assessment of Accident Risk During 
Haulage Truck and Power Shovel 
Maintenance and Recommendations 
for Improved Safety 

By Thomas J. Albin 



UNITED STATES DEPARTMENT OF THE INTERIOR 
Manuel Lujan, Jr., Secretary 

BUREAU OF MINES 
T S Ary, Director 



<> 



s 



^ 

^ 



<D 



<\ 



r y 



&b 



o 



o' 




Library of Congress Cataloging in Publication Data: 



Albin, Thomas J. 

Assessment of accident risk during haulage truck and power shovel maintenance 
and recommendations for improved safety / by Thomas J. Albin. 


p. cm. — (Information circular; 9246) 




Includes bibliographical references. 




Supt. of Docs, no.: I 28.27:9246. 




1. Dump trucks — Maintenance and repair — Safety measures. 2. Mine 
haulage — Safety measures. 3. Power shovels — Maintenance and repair — Safety 
measures. I. Title. II. Series: Information circular (United States. Bureau of 
Mines); 9246. 


TN295.U4 [TL230.2] 622 s-dcl9 [622'.8] 


88-600411 
CIP 



CONTENTS 

Page 

Abstract 1 

Introduction 2 

Methods 2 

Haulage truck maintenance accidents 2 

Cooling system 3 

Suspension system 3 

Tires 3 

Recommended actions for truck systems 3 

Cooling system 3 

Suspension system 4 

Tires 5 

Power shovel system accident analysis 5 

Hoist and hoist cable systems 6 

Swing system 6 

Summary 6 

ILLUSTRATION 

1. Hypothetical step point on truck bumper improved with grating material 4 

TABLES 

1. Accident and injury ratios for truck systems 3 

2. Accident and injury ratios for power shovel systems 6 



UNIT OF MEASURE ABBREVIATIONS USED IN THIS REPORT 

pet percent st short ton 



ASSESSMENT OF ACCIDENT RISK DURING HAULAGE TRUCK 

AND POWER SHOVEL MAINTENANCE AND 

RECOMMENDATIONS FOR 

IMPROVED SAFETY 



By Thomas J. Albin 1 



ABSTRACT 

U.S. Bureau of Mines research has found that maintenance of surface mining equipment is involved 
in slightly more than one-third (34.1 pet) of all surface mining accidents. Two groups of machines, 
haulage trucks and power shovels, accounted for over one-half of all surface mining mobile equipment 
maintenance accidents in 1978-84. Maintenance work-time histories for these machines were compared 
with accident records to identify the most hazardous-to-maintain systems within the machines. 
Recommendations to reduce the accident risk associated with maintenance of these hazardous systems 
are presented. 

'industrial engineer, Twin Cities Research Center, U.S. Bureau of Mines, Minneapolis, MN (now with 3M Co., St. Paul, MN). 



INTRODUCTION 



Accidents associated with equipment maintenance 
account for a substantial portion of all U.S. surface mining 
accidents. Maintenance and repair operations in U.S. 
surface mines, during the 1978-84 period, accounted for 
34.1 pet of all lost-time accidents and 16.5 pet of all 
fatalities. 2 This report is based on U.S. Mine Safety and 
Health Administration (MSHA) records of maintenance 
accidents that occurred in the surface mining industry from 
1978 through 1984, which identify 18,331 accidents as 
maintenance related. 3 Of these accidents, 5,776 (31.5 pet) 
occurred during the maintenance of mobile m inin g 
equipment. 

Accidents linked to maintenance work on large haulage 
trucks (50-st capacity or larger) constituted 21.2 pet of all 
accidents associated with maintenance of surface mining 
mobile equipment in the period 1978-84. During the same 



period, accidents occurring during the maintenance of 
power shovels and draglines accounted for 34.5 pet. Thus, 
research addressing maintenance safety for these two 
classes of equipment can potentially have an impact on 
55.7 pet of the total number of maintenance accidents 
involving mobile mining equipment. 

As part of its mission to increase the safety of mining 
operations, the U.S. Bureau of Mines examined 1978-84 
MSHA maintenance accident records, including 1,225 
accidents associated with off-road haulage trucks of 50-st 
or larger capacity and a sample of 100 accidents from 
approximately 2,000 associated with power shovels. This 
report identifies highly hazardous areas of haulage truck 
and power shovel maintenance and suggests modifications 
to machines or procedures that would improve 
maintenance safety. 



METHODS 



In order to evaluate the relative hazard of working on 
the various systems that comprise surface mining 
machines, the Bureau collected maintenance and repair 
work-time records from three surface iron mines. These 
work-time data were then classified by the system worked 
on. Accidents that occurred during maintenance and 
repair activity were then assigned to the same set of 
systems. 

A statistical analysis was used to evaluate the 
contribution of each truck or shovel system to the total 
accident frequency and injury severity, relative to the 
portion of the total maintenance time spent maintaining or 
repairing that system. That is, systems with a high 
percentage of total accident frequency and a low 
percentage of work time are highly hazardous, and systems 
with a low percentage of total accidents and a high 
percentage of work time are less hazardous. These 
relative values were expressed as ratios. 

The first ratio calculated was the percentage of total 
accident frequency (total number of accidents) divided 
by the percentage of total maintenance time spent 



maintaining or repairing the particular system. The second 
ratio calculated was the percentage of total injury severity 
divided by the percentage of total maintenance time spent 
maintaining or repairing the particular system. Injury 
severity is defined as the sum of lost workdays and 
statutory days charged, plus one-half of the restricted 
workdays. 

Statistical confidence intervals were established for 
these ratios. Confidence intervals specify a range of values 
around an overall mean, in this case, the overall mean of 
a group of ratios. The more distant the severity or 
frequency ratio of a particular system from the average of 
all systems, the more or less hazardous the system is, 
depending on whether the ratio is more or less than the 
average. Those ratios that are more distant, in the sense 
of being farther than a statistically specified distance from 
the average of all ratios, indicate systems that are more 
hazardous to work on than the average system. The 
statistical technique allows a statement of confidence that 
the systems are correctly identified as hazardous. In this 
report, that confidence level is 95 pet. 



HAULAGE TRUCK MAINTENANCE ACCIDENTS 



Accidents involving haulage trucks have been analyzed 
to determine the truck system being worked on at the time 
of the accidents. This information, listed in table 1, was 
obtained from MSHA accident narratives. Using 
maintenance and repair work-time histories obtained from 



Xong, D. A. An Analysis of Off-Highway Haulage Truck 
Maintenance and Repair Accidents, 1978-84. BuMines IC 9139, 1987, 
15 pp. 

3 Work cited in footnote 2. 



surface iron operations, the percentage total of all work 
time spent in maintaining each truck system was also 
estimated. The percentage total of all accidents in the 
sample involving each system was then compared with the 
percentage of work time devoted to each system to identify 
the systems that were most hazardous. Accident frequency 
and injury severity were both considered. 

The overall average injury severity ratio for trucks was 
1.98 days, and the overall accident frequency ratio for 
trucks was 2.034 days. Three truck systems were identified 
as having higher than average accident frequency and 



injury severity ratio: the cooling, suspension, and tire 
systems. 

Table 1. -Accident and injury ratios for truck systems 

Ratio, Ratio, Pet total 
System actual-expected actual-expected accidents 
accident frequency Injury severity 

Air 0.7698 0.2805 1.0 

Blower 1.1400 .0702 .5 

Box .4438 .6267 7.3 

Brakes 1.5663 1.6888 6.1 

Cab 1.0265 .7478 2.3 

Cooling ^.8380 1 4.8102 10.5 

Electric brake . .2292 .0069 .3 

Electric 1.0074 .9448 5.5 

Engine 1.3115 1.7010 22.1 

Exhaust 1.0813 .3415 1.3 

Frame .8763 .7268 6.8 

Fuel 2.3140 1.4535 2.0 

Hydraulic 1.1350 .5714 5.8 

Fladio .4857 (2) .2 

Steering 1.4872 2.4402 3.5 

Suspension . . 1 8.4386 ' 10.4737 4.8 

Tires 1 8.2092 1 6.7449 16.1 

Wheel motors . .2228 .0184 1.3 

Overall 

average 2.034 1^98 NAp 

NAp Not applicable. 

^cessively high accident frequency or injury severity. 

Undefined. 

Source: Based on MSHA accident records, 1978-84, and work- 
time records from 3 mines. 

COOLING SYSTEM 

Accidents involving the cooling system were broken 
down into two subgroups, one group of 27 that occurred in 
the field and another group of 40 that occurred in the 
shops. 

Field accidents were predominantly (70 pet) the results 
of opening hot cooling systems, which caused scalding by 
the hot coolant. Another 25 pet of these accidents were 
slip-and-fall-type accidents. All of the falls occurred 
because of footing problems; that is, they resulted from 
insufficient traction on the surface on which the individual 
was standing, including deck surfaces, ladders, and tires. 



Shop accidents were more diverse. A major, 
identifiable class of accidents is falls, which accounted for 
57 pet of all shop accidents. The falls occurring in the 
shop also resulted, primarily, from footing problems. 
Slipping handtools and overexertion of the worker 
accounted for approximately 13 pet each of the accidents. 

SUSPENSION SYSTEM 

Of a total of 35 accidents associated with the suspension 
system, 35 pet involved the fall of large, unsecured parts 
on workers. In another 30 pet, workers overexerted 
themselves, primarily while pushing or pulling on 
wrenches. An additional 10 pet was workers' falling while 
working on the suspension system. 

TIRES 

A total of 63 accidents involving tire work were 
examined. Of these, 19 pet resulted from explosions of the 
tire. Approximately 25 pet of the explosions occurred 
while the tire was on the truck. Some of the explosions 
involved the mate of the tire that was actually being 
worked on. In most of these accidents, the injured 
individual was struck by projectiles, either parts of the tire 
or rim, or dust and dirt kicked up by the explosion. 

Eighteen percent of the tire accidents involved the fall 
of unsecured tires on individuals while the tires were being 
moved. In another 2 pet of the cases, the chain or cable 
used to secure the tire was inadequate and failed under 
load. Thus, one of five tire accidents resulted from moving 
inadequately secured tires. 

Fourteen percent of the tire accidents involved 
overexertion of the worker. The overexertion injuries 
resulted from both lifting and push-pull actions. 

Inadequate eye protection accounted for approximately 
10 pet of all tire injuries, as did slipping handtools and 
"caught in" injuries. "Caught in" injuries typically involved 
catching a hand or fingers between a tire and the rim, or 
between a retaining ring and the seating groove. 

Falls accounted for 6 pet of the tire accidents. 



RECOMMENDED ACTIONS FOR TRUCK SYSTEMS 



COOLING SYSTEM 

Cooling system accidents that occurred in the field are 
predominantly the result of opening hot, pressurized 
cooling systems. Often this appears to be the result of the 
operator's, or less frequently the mechanic's, impatience in 
waiting for the system to cool sufficiently before opening 
the system for inspection or servicing. 

A general approach to safety engineering is to first 
formulate a solution to the problem. A simple solution 
would be to develop a "sight glass" appropriate to field 
conditions that could be added to the cooling systems. 
This would indicate coolant levels while the system is 



closed. A similar approach would be to add a transparent 
overflow reservoir, similar to those found in automobiles, 
which indicates fluid levels while the cooling system is 
closed. 

If impatient operators and mechanics are going to open 
hot cooling systems, a straightforward solution to this 
problem would be the development of a method for the 
remote release of pressure in the cooling system. Using 
such a device, the operator or mechanic could vent a hot 
cooling system from a safe distance, thus avoiding 
scaldings. If coolant loss is unacceptable, the system could 
be modified so that it would vent into a reservoir from 
which the coolant could be recovered. 



Another approach would be to install locking caps and 
limit the distribution of keys. Kits to add locks to radiator 
caps are available from some Original Equipment 
Manufacturers (OEM). These are sometimes sold as 
antivandalism kits. This would limit the number of 
individuals who could open radiators to those who 
presumably know the risks involved. It would also build in 
some delay time, possibly allowing the system to cool 
down. 

A secondary approach to safety engineering is to train 
the individuals involved to recognize hazards. Information 
regarding the danger entailed in opening a hot cooling 
system should be included in operator training. Finally, 
warning signs or tags should be prominently displayed in 
the vicinity of the cooling system. 

The second most common source of accidents involving 
field maintenance or repair of the cooling system is slips 
and falls. The cause of these accidents can be directly 
attributed to the condition of the surface on which the 
individual was standing. In some cases, these surfaces 
were inappropriate, such as tires. In other cases, they 
were more reasonable, e.g., decks and bumpers. In all 
cases, they involved insufficient frictional forces, primarily 
because of lowered coefficients of friction. Frequently, this 
decrease in friction was due to lubricants, such as fluids or 
granular material (sand, dirt, fine ore spillage, etc.). 

An engineering solution would be to identify all 
positions where a worker might stand within a reasonable 
reach envelope of major cooling system components. 
These standing points could then be improved by attaching 
grating material. This material has the advantage of 
allowing small granular material and fluid to drain through 
and has an intrinsically high coefficient of friction due to 
its rough surface. A schematic of such an installation is 
presented in figure 1. 

The majority of shop accidents (57 pet) involving the 
cooling system are falls. About two-thirds of these 
accidents also resulted from slips while standing on truck 
surfaces as described above, and these surfaces would 
benefit from improved traction. About one-third of these 
injuries in the shop resulted from the absence of railings 
on the workstand the individual was using. Although space 
limitations may not be as great a problem while individuals 
work on the cooling system, this problem often prevents 
the use of either workstands or guardrails, or both, during 
maintenance. The development of guiderails for purchase 
or construction of an adjustable-height workstand with 
guardrails that could be used within confined spaces could 
improve maintenance safety. As a starting point, such a 
workstand could be similar to the "bucket" of a cherry 
picker, essentially a cylinder enclosing the worker. 

A second approach would be to use safety lines. 
Attachment points for these lines could be affixed to the 
machine. 

Overexertion of the worker and slipping handtools 
accounted for approximately 26 pet of shop accidents. 
Because posture is often involved in such injuries, the 
location of improved surfaces for standing so that major 
components are within standard reach envelopes could 




Figure 1 .-Hypothetical step point on truck bumper improved 
with grating material. Detailed section (circled) shows grating. 



help to reduce overexertion injuries. Trainig to avoid high- 
risk postures would also be beneficial. 

In summary, cooling system injury accidents could be 
reduced through 

1. Development of a durable sight glass or transparent 
overflow reservoir to indicate coolant levels; 

2. Development of a remotely activated pressure 
release for haul truck radiators; 

3. Purchase and installation of locking radiator caps; 

4. Inclusion of warnings in the operator's and 
mechanic's training as to the hazards of opening hot 
cooling systems; 

5. Location and improvement of the footing at 
positions on the truck such as bumpers, decks, etc., where 
a mechanic or operator might stand to work on or service 
the cooling system, whether in the shop or in the field; 

6. Development of a workstand with adequate railings 
and toeboards that could be used within the confined 
spaces of an off-road haulage truck; 

7. Use of safety belts and safety lines; 

8. Training for maintenance personnel in avoiding high- 
risk postures, including lifting and push-pull exertions, 
while exerting force. 

SUSPENSION SYSTEM 

Ninety-five percent of all maintenance accidents 
involving the suspension system occurred in a shop, as 
opposed to a field location. Thirty-five percent of 
accidents that occurred during maintenance of the 
suspension system resulted from unsecured parts, which 
fell and struck workers. An additional 30 pet were 
overexertion injuries, and 10 pet were falls. 



Characterization of work practices at mines with good 
truck maintenance safety records emphasizes that the 
suspension system components are always secured against 
movement. One mine's procedure involves clamping the 
suspension system component to a forklift. This gives the 
ability to move the component as well as to secure it. This 
mine uses a shop-fabricated bracket to clamp the system 
component to the forklift. Development of specifications 
and drawings for a similar fixture for dissemination to 
mines would assist in accident prevention. Similarly, plans 
for alternative shop-fabricated systems of securing and 
moving suspension system components could be developed. 

Falls and some overexertion injuries are related to 
workstand characteristics. As previously mentioned, the 
absence of railings may increase the severity of an injury, 
and the frictional properties of the surface may increase 
the probability of an accident. Workers exerting force 
while assuming an awkward posture because of the height 
of the workstand are at increased risk of an overexertion 
injury. Workers attempting to exert the required forces 
may slip because the workstand surface is inadequate and 
may fall because of absent railings or toeboards. 

Overexertion injuries resulting from lifting or 
attempting to lift system components could be reduced by 
ensuring the availability and use of lifting devices such as 
light cranes or forklifts or other fixtures as described 
above. Training in safe lifting techniques should also be 
provided. 

In summary, suspension system injuries could be 
reduced by 

1. Development of a fixture or fixtures to be mounted 
on a forklift for the purpose of securing and moving 
suspension system components; 

2. Development of a similar fixture capable of 
supporting and moving system components without the use 
of a forklift; 

3. Development of an adjustable-height workstand that 
can be used within the confined spaces of a haulage truck 
as previously discussed; 

4. Training for workers in safe lifting and push-pull 
procedures, including recommended postures and load 
limits. 

TIRES 

Nineteen percent of all tire accidents resulted from 
the explosion of the tire. Eighty-three percent of the 



explosions could have been prevented if the tire and its 
mate were both deflated before any work was done on 
them, including removal from the vehicle. The 
recommended action is to emphasize this in the training of 
individuals who work on, or may be expected to work on 
tires. 

Eighteen percent of all tire accidents resulted from the 
fall of tires and/or rims on workers while the tires were 
being transported, installed, or removed from the vehicle. 

Another 2 pet of all tire accidents resulted from failure 
of the chain or cable to support the tire during movement 
or transportation. These accidents could be prevented by 
emphasizing the importance of supporting the tires while 
they are being moved. Tire workers should be made 
aware of the required chain or cable strength necessary to 
support tires. Equipment capable of moving and 
supporting tires should also be available for the worker's 
use. 

Overexertion injuries accounted for 14 pet of all tire 
injuries. Training in proper lifting techniques, especially 
when to lift and when to use a mechanical assist, should be 
provided periodically. 

Inadequate eye protection, slipping handtools, and 
catching hands between tires and rims accounted for 30 pet 
of all tire accidents. These accidents are best addressed 
by changing worker behavior, which could be done through 
training and behavioral management of safe working 
practices. 

A final 6 pet of tire accidents were falls that resulted 
from poorly constructed workstands. The need for well- 
designed workstands with adequate toe and guardrails has 
already been discussed. 

In summary, recommended actions for improving tire 
safety are 

1. Deflating the tires, including both tires of dual 
mounts, prior to any work on tires; 

2. Providing adequate supports for tires while they are 
being removed, transported, or installed on trucks, and 
developing guidelines for adequate support of cables or 
chains; 

3. Providing all tire workers appropriate training in 
proper lifting and exerting push-pull force; 

4. Ensuring that personal protective equipment, such 
as eye protection, is used; 

5. Utilizing adequate workstands, including toeboards 
and guardrails. 



POWER SHOVEL SYSTEM ACCIDENT ANALYSIS 



An analysis similar to that performed on trucks was 
conducted for accidents that occurred while working on 
power shovels. That is, the frequency and injury severity 
of accidents while working on various power shovel 
systems were compared with the time spent maintaining 
and repairing those systems. The results are presented in 
table 2. 



Three power shovel systems were identified as highly 
hazardous in terms of the frequency of accidents relative 
to the time spent working on the systems. These systems 
are the hoist, hoist cable, and swing system. Two systems 
were identified as highly hazardous in terms of the severity 
of their associated injuries; they are the hoist cable and the 
swing systems. 



Table 2. -Accident and injury ratios for power shovel systems 

— Ratio, Ratio, Pet total 

System actual-expected actual-expected accidents 

accident frequency injury severity 

Air 6\94 017 33 

Boom .65 .23 7.8 

Bucket .96 .61 28.1 

Cab .40 .13 .6 

Car body .69 1.40 5.0 

Electrical 1.10 2.76 6.9 

Hoist H2.37 3.55 11.5 

Hoist cable .. . H3.65 '8.94 11.6 

Lubrication... 1.22 1.51 4.5 

Propel .25 .10 7.8 

Superstructure 2.73 4.47 4.1 

Swing 1 6.62 * 19.98 8.6 

^cessively high accident frequency or injury severity. 

Source: Based on MSHA accident records, 1978-84, and work- 
time records from 3 mines. 

Because of the larger sample of power shovel accidents, 
it was decided to use a random sample of power shovel 
accident narratives, rather than examine all narratives, as 
was done with trucks. A random sample of 100 power 
shovel accidents was selected from all MSHA power shovel 
accident records for the period 1978-84. The following 
sections are based on this sample. 

HOIST AND HOIST CABLE SYSTEMS 

Although the hoist and hoist cable systems combined 
account for only 1.75 pet of power shovel maintenance and 
repair work time, 20 pet of all power shovel maintenance 
accidents occurred while working on these two systems. 

The predominant types of accidents while working on 
the hoist and hoist cable systems are being hit by the cable 
or flying chips (40 pet), slips and falls (30 pet), and being 
caught in the cable (25 pet). In 6 pet of the "hit by" 
accidents, the worker was struck by a whipping cable end. 
In the remainder of the "hit by" accidents, chips flew off of 
pins, etc., which were being driven with hammers. Fifty 



percent of the slips and falls occurred when a worker was 
standing on a cable drum while it was turning. The 
remainder were due to decreased surface friction. The 
"caught in" injuries typically involved hands or fingers 
caught between the cable and some other object, such as 
the drum. 

The most readily addressable of these accidents appear 
to be falls and being hit by chips. Falls have been 
discussed in detail under truck system accidents. A 
worker's being struck by a chip while driving a pin, etc., is 
a very common type of power shovel accident. A potential 
method for reducing the number of such accidents is to 
use a soft metal hammer. A soft metal hammer would 
reduce the number of chips and may actually be more 
efficient than a steel hammer in converting swing energy 
in actual work. 

A second method of driving or removing pins would be 
to utilize a hydraulic jack. In some instances, this may 
require the development of jigs or fixtures to hold the 
hydraulic tool in position. 

SWING SYSTEM 

Seven percent of all accidents in the sample involved 
the swing system. All of these accidents occurred when an 
object, such as a tool, fell and struck a worker below. In 
a situation where work will be carried on at different 
levels, any protection, such as a portable canopy, for the 
lower-level worker would be appropriate. 

Recommendations for improved safety while main- 
taining power shovels are 

1. Improved access, including better means of access, 
and better housekeeping of walking surfaces; 

2. Utilization of soft metal hammers or hydraulic tools 
for driving or removing pins; 

3. Protection from falling hand tools and from small 
parts for workers at lower levels. 



SUMMARY 



Three haulage truck systems were identified as most 
hazardous to work on in terms of both accident frequency 
and injury severity. These systems are the cooling, the 
suspension, and tires. Three power shovel systems were 
identified as most hazardous in terms of accident 
frequency. These systems were the hoist, hoist cable, and 
the swing. Two power shovel systems, the hoist cable and 
the swing, were identified as most hazardous in terms of 
injury severity. Some of these accidents are amenable to 
engineering intervention. Others may be more readily 
addressed through behavioral intervention. 

Falls are a serious type of maintenance accidents, as has 
been seen in the analysis of these highly hazardous 
systems. Falls accounted for approximately 25 pet of all 
surface mine haulage truck maintenance accidents. In the 
sample of 100 power shovel accidents, 44 pet of all 



accidents involved falls, mostly from ladders. An 
underlying theme of these falling accidents is the apparent 
inadequacy of current workstands or other means of access 
to the machines. Some of the design shortfalls include the 
lack of toeboards and guardrails coupled with low-friction 
work surfaces. Another serious problem is the space 
constraint imposed by working within the haulage trucks 
and power shovels. Many workstands cannot be used in 
confined spaces. 

Many falls result from inadequate footing on the 
surfaces on which mechanics stand while performing 
maintenance tasks. The location of such standpoints and 
improvement of these surfaces with nonslip surfaces, such 
as grating, would decrease the number of falling accidents, 
as would the use of safety belts and lines. Currently, many 
standpoints are structural elements of the machine and are 



surfaces on which workers stand. Spilled liquids and 
particulate matter, which are allowed to accumulate, are 
examples of poor housekeeping, which increases the risk 
of a falling accident. 

A second general problem is parts that are not secured. 
The development of new workstands with toeboards 
capable of being used within confined spaces, or the 
utilization of existing systems with toeboards, would de- 
crease the number of accidents where system components 
may fall on individuals. 

Finally, a large portion of all maintenance accidents 
may be best addressed by behavioral intervention. This 
type of behavioral intervention would consist of initial 
training in workplace hazards and safe working methods, 



followed by behavioral management strategies for 
maintaining safe work practices. 

Injuries while working on haulage trucks and power 
shovels account for a significant portion (55.7 pet) of 
mobile surface mining equipment maintenance accidents. 
The systems identified within this report are the most 
hazardous systems to maintain and repair on these 
machines, in terms of both accident frequency and injury 
severity. The suggested solutions to these problems are 
primarily (1) gaining access to work areas on the 
machines, (2) protecting the employee in the work area, 
and (3) training the worker in safe work practices, such as 
safe lifting techniques. 



m 



t O 

■< -n 



O 

> 



o 

s 
•o 
2 t 



CO 



m 

m CO 
I CO 



3- 

5-m 

° 2 
- 3 8 



IS) J 

8s 

■C» CO 
00 

o 
o 



03 C 
5 CO 



O "O 
5. CD 



3" 
fi> 

5' 



m 
D 

c 
> 

i- 

O 

-o 

13 

o 

33 



3 

m 



O 

-< 
m 

33 



413- 90 




\s 



» <K « 

* .'dfefc-. *^/ .^&" **<** V 














* 4>^ - ' 



W 
^ 









\> 5 ♦ • 



«b^ 



»* T. 



**o« 













v* .•« 













%<** 



* ^ *♦ -*!qRK* / % v 








•/ \*%&j> v ! ^*/ \-*&y v^v v-^^v ^ 

» 9 ...;^:..^ ^..^fe-X y.iiS:..** ^..ittfc.%. >*.:a:..^ ,.^%^&r- 















-w 7 






~\f 



4* ^ ' 






•^•-•\ /&&?°* y.-^fe.\ ^<£&y >- 



i: ^o* . 



^o*. 






: w .: 



.4^ 




»bi? 



* AT *Ce. • 

«^*< .V^SV. "^ c fa * # 












HECKMAN 

BINDERY INC. 

# NOV 90 
N. MANCHESTER, 
INDIANA 46962 







«5°xv 



^ 





^ ^ .^ Stair-. ^ < 






o_ 




^°/» :^i*g^.' *p^ 



• .^ 



by 




♦ „^ 



